The most exciting modern rivalry in men's tennis will be reignited after Sinner rallied past world No.12 Tommy Paul 1-6 6-0 6-3 in the semi-finals on Friday as he attempts to become the first Italian man to lift the Rome trophy since Adriano Panatta in 1976.
Earlier, Alcaraz had advanced to his first Rome final by beating Lorenzo Musetti 6-3 7-6 (7-4), setting up the showdown that the tennis world wanted to see again.
For Sunday's final will mark the first meeting between the pair since October, when Alcaraz won a thrilling China Open final in a third-set tiebreaker.
Alcaraz holds a 6-4 edge in his career meetings with Sinner and has won three straight against his biggest rival.
But Sinner has not lost since that defeat to Alcaraz in Beijing and is on a 26-match winning streak. He's playing his first tournament since he won his third grand slam title at the Australian Open in January.
"He's playing great. I've been watching his matches," Alcaraz said. "His level is really high right now. Every time that I play against him is always a battle, always really, really tough. I kind of enjoy those moments."
Sinner cranked up his level to near perfection in a rout of Casper Ruud in the quarter-finals on Thursday.
Against Paul, though, Sinner made unforced errors in the first set while his American opponent hit shot after shot on the lines.
The Italian, though, quickly turned the match around.
"Everybody saw the game against Casper," Alcaraz said. "It's a huge level."
Sinner is the first Italian man in the Rome final since Panatta lost the 1978 title match to Bjorn Borg, and Alcaraz noted that playing Sinner before his home crowd will be "even more challenging."
Sinner's fans have been out in full force for all of his matches, many of them wearing wigs and hats in orange — his theme color. One fan held aloft a sign during the semi-final that translated from Italian to "Sinner, we missed you."
In February, Sinner agreed to a settlement with the World Anti-Doping Agency that raised questions, since the three-month suspension conveniently allowed him not to miss any grand slams and come back at his home tournament.
It's the third final in three clay-court events this season for Alcaraz, who won the Monte Carlo Masters and finished runner-up in the Barcelona Open. He withdrew from the Madrid Open because of injury.
The third-ranked Alcaraz withdrew from the Madrid tournament with an upper right leg issue and also had a left leg injury. In Rome, he has been wearing a long black brace covering the upper portion of his right leg stretching down to just below his knee.
A four-time grand slam champion already by the age of just 22, Alcaraz is preparing to defend his title at the French Open, starting at the end of next week.
